HOUSTON—Former President George H.W. Bush is calling former British Prime Minister Margaret Thatcher one of the 20th century's fiercest advocates of freedom and free markets.

Thatcher died Monday in London of a stroke. She was 87.

Bush, in a statement from Houston, says Thatcher was a leader of rare character who "carried high the banner of her convictions." And he says her principles in the end helped shape a better, freer world.

Bush says his family's personal grief is compounded by the knowledge America has lost one of its staunchest allies ever. He also says he's certain her "sterling record of accomplishment" will inspire future generations.

Bush's first two years in office from 1989 to 1990 coincided with Thatcher's final two years as British prime minister.